The present invention relates to a vehicle tire. Specifically, the invention relates to a pneumatic vehicle tire having a groove wall lining that reduces the formation of anomalies causing subjective user dissatisfaction.
Tires, especially commercial vehicle tires, may be removed from service due to anomalies on the tread region. These anomalies are depressions in the tread rib or tread block. The anomalies can be caused by unequal normal stress distribution laterally across the rib or block.
The stress concentration occurs at the edges of the tread rib or block. The stress concentration at the edges of the tread rib or block is known as the edge effect. The central portion of the tread rib or block experiences a lower stress than the edges of the tread rib or block. The stress at the edge of the tread rib or block may be approximately twice as large as the stress at the central portion of the tread rib or block. The stress concentration at the edges of the tread rib or block typically causes anomalies to form at the edges of the tread rib or block.
Once an anomaly forms at the edge of the rib or block, the anomaly will propagate to the remainder of the rib or block; and often to adjacent ribs or blocks. The propagation of the anomaly occurs quickly as the tire continues to roll.
The decision to remove a tire is subjective and may depend on the location of the tire on the truck/trailer combination. Generally, a driver can feel an anomaly on a steering tire by the ride comfort and handling of the vehicle. In that case, the driver pulls the tire when uncomfortable with the ride and/or handling of the vehicle. However, if a tire having an anomaly is a drive tire or is located on the trailer, the driver may not sense any discomfort. The driver may, however, hear an increase in tire noise. If the driver does not sense discomfort or an increase in noise, the driver will pull the tire during a subsequent visual inspection of the vehicle.
The removal of a tire due to anomalies causing subjective user dissatisfaction is premature when considering the portions of the tire without the anomaly. The portions of the tire without the anomaly are capable of substantial additional service on the vehicle. Extending the time until the onset of an anomaly or decreasing the severity of the anomaly once found may extend the life of the tire. The extended life of the tire reduces the cost of purchase and installation of new tires. In the commercial trucking field, these potential cost savings are significant.
Thus, it is an object of the present invention to provide a tire with an improved tread portion which reduces the formation of anomalies causing subjective user dissatisfaction.
It is a further object of the present invention to provide a tread portion which eliminates the edge effect or exhibits a reduced edge effect, defined as the high normal stress value at the edges of a tread rib or block as compared to the center portion of a tread rib or block.
It is a further object of the present invention to provide a tread portion which more uniformly distributes normal stress laterally across a tread rib or block.